The coach isn't average,he is plain bad.Maybe you could argue he was average/decent in 17/18,but since then it's getting worse and worse.
First of all,he has no charisma and it is clear that he has no real control of the locker room.That means that he can never inspire the players to get better or to try more.
Secondly,his fixation with certain players is extremely frustrating.Playing an underperforming,old and fat Suarez every single match and never trying something new.Maybe a potential new experiment on attack wouldn't turn out to be effective,but at least give Luis a rest.Of course,I HAVE to mention Rakitic,who in most games was either average or extremely bad,BUT he never got benched.There are more examples like Busquets.
Finally,the tactics themselves are the worst tactics I've seen from any Barca coach the last 15 years,except for the last few months under Tata Martino.
-Arthur was one of the best players last year and despite outperforming every single midfielder on the squad and despite being the only guy that was actually trying to push the ball forward and that could beat the opponents' pressure (*cough* Rakitic *cough*),Valverde decided to bench him towards the end of the season.And right now,he still seems to favor Roberto or Rakitic or Vidal over him.
-He is already playing FDJ out of position.Instead of playing him as a CDM or as a box-to-box midfielder,he is playing him as a left winger(!!!!!!!!).Simply unbelievable!And I bet that the only reason that he is giving him a starting position is because FDJ is a big signing.
-So instead of having a midfield of Arthur-Busi-FDJ,or Arthur-FDJ-Vidal or even Arthur-FDJ-Roberto we will have the "pleasure" to watch a hybrid midfield of FDJ as a LM,Busi/Raki as a CDM,Roberto/Vidal as a CM and Athur on the bench.
-Furthermore,instead of giving the keys of the build-up play to FDJ and Arthur, Valverde's chosen one is Jordi Alba.Alba is a great LB,don't get me wrong.but he shouldn't be the team's second creator after Messi!
If I could make the decisions,I would do the following:
-Bench Suarez and give him minutes against the weaker La Liga teams.Have him as a sub against good teams and in the CL.
-Play Leo as a false 9 and have Dembele as a RW.Griezmann would be a hybrid LW/striker(when he moves centrally,Alba would make a run as a LW)
-Play BOTH Arthur and FDJ at the midfield along with Raki/Busi/Roberto/Vidal.BUT they would play as centrally as possible,so that they can work with each other and with Messi,instead of being the full backs' merchants.